unset ACTION
unset AD_HOC_CODE_SIGNING_ALLOWED
unset ALTERNATE_GROUP
unset ALTERNATE_MODE
unset ALTERNATE_OWNER
unset ALWAYS_SEARCH_USER_PATHS
unset ALWAYS_USE_SEPARATE_HEADERMAPS
unset APPLE_INTERNAL_DEVELOPER_DIR
unset APPLE_INTERNAL_DIR
unset APPLE_INTERNAL_DOCUMENTATION_DIR
unset APPLE_INTERNAL_LIBRARY_DIR
unset APPLE_INTERNAL_TOOLS
unset APPLY_RULES_IN_COPY_FILES
unset AR
unset ARCHS
unset ARCHS_STANDARD
unset ARCHS_STANDARD_32_64_BIT
unset ARCHS_STANDARD_32_BIT
unset ARCHS_STANDARD_64_BIT
unset ARCHS_STANDARD_INCLUDING_64_BIT
unset ARCHS_UNIVERSAL_IPHONE_OS
unset ASM
unset AVAILABLE_PLATFORMS
unset BUILD_COMPONENTS
unset BUILD_DIR
unset BUILD_ROOT
unset BUILD_STYLE
unset BUILD_VARIANTS
unset BUILT_PRODUCTS_DIR
unset CACHE_ROOT
unset CC
unset CCHROOT
unset CFLAGS
unset CHMOD
unset CHOWN
unset CLASS_FILE_DIR
unset CLEAN_PRECOMPS
unset CLONE_HEADERS
unset CODESIGNING_FOLDER_PATH
unset CODE_SIGNING_ALLOWED
unset CODE_SIGNING_REQUIRED
unset CODE_SIGN_CONTEXT_CLASS
unset COMBINE_HIDPI_IMAGES
unset COMMAND_MODE
unset COMPOSITE_SDK_DIRS
unset COMPRESS_PNG_FILES
unset CONFIGURATION
unset CONFIGURATION_BUILD_DIR
unset CONFIGURATION_TEMP_DIR
unset CONFIG_SITE
unset COPYING_PRESERVES_HFS_DATA
unset COPY_PHASE_STRIP
unset COPY_RESOURCES_FROM_STATIC_FRAMEWORKS
unset CP
unset CREATE_INFOPLIST_SECTION_IN_BINARY
unset CURRENT_ARCH
unset CURRENT_VARIANT
unset CXX
unset CXXFLAGS
unset DEAD_CODE_STRIPPING
unset DEBUGGING_SYMBOLS
unset DEBUG_INFORMATION_FORMAT
unset DEFAULT_COMPILER
unset DEFAULT_KEXT_INSTALL_PATH
unset DEPLOYMENT_LOCATION
unset DEPLOYMENT_POSTPROCESSING
unset DERIVED_FILES_DIR
unset DERIVED_FILE_DIR
unset DERIVED_SOURCES_DIR
unset DEVELOPER_APPLICATIONS_DIR
unset DEVELOPER_BIN_DIR
# unset DEVELOPER_DIR # Used to detect Xcode environment
unset DEVELOPER_FRAMEWORKS_DIR
unset DEVELOPER_FRAMEWORKS_DIR_QUOTED
unset DEVELOPER_LIBRARY_DIR
unset DEVELOPER_SDK_DIR
unset DEVELOPER_TOOLS_DIR
unset DEVELOPER_USR_DIR
unset DEVELOPMENT_LANGUAGE
unset DO_HEADER_SCANNING_IN_JAM
unset DSTROOT
unset DT_TOOLCHAIN_DIR
unset DWARF_DSYM_FILE_NAME
unset DWARF_DSYM_FILE_SHOULD_ACCOMPANY_PRODUCT
unset DWARF_DSYM_FOLDER_PATH
unset EFFECTIVE_PLATFORM_NAME
unset EMBEDDED_PROFILE_NAME
unset ENABLE_HEADER_DEPENDENCIES
unset ENTITLEMENTS_REQUIRED
unset EXCLUDED_INSTALLSRC_SUBDIRECTORY_PATTERNS
unset EXCLUDED_RECURSIVE_SEARCH_PATH_SUBDIRECTORIES
unset FILE_LIST
unset FIXED_FILES_DIR
unset FRAMEWORK_VERSION
unset GCC3_VERSION
unset GCC_GENERATE_DEBUGGING_SYMBOLS
unset GCC_INLINES_ARE_PRIVATE_EXTERN
unset GCC_OPTIMIZATION_LEVEL
unset GCC_PFE_FILE_C_DIALECTS
unset GCC_PREPROCESSOR_DEFINITIONS
unset GCC_SYMBOLS_PRIVATE_EXTERN
unset GCC_THUMB_SUPPORT
unset GCC_TREAT_WARNINGS_AS_ERRORS
unset GCC_VERSION
unset GCC_VERSION_IDENTIFIER
unset GENERATE_MASTER_OBJECT_FILE
unset GENERATE_PKGINFO_FILE
unset GENERATE_PROFILING_CODE
unset GID
unset GROUP
unset HEADERMAP_INCLUDES_FLAT_ENTRIES_FOR_TARGET_BEING_BUILT
unset HEADERMAP_INCLUDES_FRAMEWORK_ENTRIES_FOR_ALL_PRODUCT_TYPES
unset HEADERMAP_INCLUDES_NONPUBLIC_NONPRIVATE_HEADERS
unset HEADERMAP_INCLUDES_PROJECT_HEADERS
unset HEADER_SEARCH_PATHS
unset ICONV
unset INFOPLIST_EXPAND_BUILD_SETTINGS
unset INFOPLIST_OUTPUT_FORMAT
unset INFOPLIST_PREPROCESS
unset INSTALL
unset INSTALL_DIR
unset INSTALL_GROUP
unset INSTALL_MODE_FLAG
unset INSTALL_OWNER
unset INSTALL_ROOT
unset IPHONEOS_DEPLOYMENT_TARGET # !
unset JAVAC_DEFAULT_FLAGS
unset JAVA_APP_STUB
unset JAVA_ARCHIVE_CLASSES
unset JAVA_ARCHIVE_TYPE
unset JAVA_COMPILER
unset JAVA_FRAMEWORK_RESOURCES_DIRS
unset JAVA_JAR_FLAGS
unset JAVA_SOURCE_SUBDIR
unset JAVA_USE_DEPENDENCIES
unset JAVA_ZIP_FLAGS
unset JIKES_DEFAULT_FLAGS
unset KEEP_PRIVATE_EXTERNS
unset LD
unset LDFLAGS
unset LD_DEPENDENCY_INFO_FILE
unset LD_GENERATE_MAP_FILE
unset LD_MAP_FILE_PATH
unset LD_NO_PIE
unset LD_QUOTE_LINKER_ARGUMENTS_FOR_COMPILER_DRIVER
unset LEGACY_DEVELOPER_DIR
unset LEX
unset LIBRARY_FLAG_NOSPACE
unset LIBRARY_KEXT_INSTALL_PATH
unset LINKER_DISPLAYS_MANGLED_NAMES
unset LINK_FILE_LIST_normal_armv7
unset LINK_WITH_STANDARD_LIBRARIES
unset LOCAL_ADMIN_APPS_DIR
unset LOCAL_APPS_DIR
unset LOCAL_DEVELOPER_DIR
unset LOCAL_LIBRARY_DIR
unset MAC_OS_X_PRODUCT_BUILD_VERSION
unset MAC_OS_X_VERSION_ACTUAL
unset MAC_OS_X_VERSION_MAJOR
unset MAC_OS_X_VERSION_MINOR
unset MAKEFLAGS
unset MAKELEVEL
unset MFLAGS
unset MODULE_CACHE_DIR
unset NATIVE_ARCH
unset NATIVE_ARCH_32_BIT
unset NATIVE_ARCH_64_BIT
unset NATIVE_ARCH_ACTUAL
unset NO_COMMON
unset OBJDUMP
unset OBJECT_FILE_DIR
unset OBJECT_FILE_DIR_normal
unset OBJROOT
unset ONLY_ACTIVE_ARCH
unset OPTIMIZATION_LEVEL
unset OS
unset OSAC
unset OTHER_CFLAGS
unset OTHER_CPLUSPLUSFLAGS
unset OTHER_LDFLAGS
unset PASCAL_STRINGS
unset PATH_PREFIXES_EXCLUDED_FROM_HEADER_DEPENDENCIES
unset PKGINFO_FILE_PATH
unset PLATFORM_DEVELOPER_APPLICATIONS_DIR
unset PLATFORM_DEVELOPER_BIN_DIR
unset PLATFORM_DEVELOPER_LIBRARY_DIR
unset PLATFORM_DEVELOPER_SDK_DIR
unset PLATFORM_DEVELOPER_TOOLS_DIR
unset PLATFORM_DEVELOPER_USR_DIR
unset PLATFORM_DIR
unset PLATFORM_NAME
unset PLATFORM_PREFERRED_ARCH
unset PLATFORM_PRODUCT_BUILD_VERSION
unset PLIST_FILE_OUTPUT_FORMAT
unset PRECOMPS_INCLUDE_HEADERS_FROM_BUILT_PRODUCTS_DIR
unset PRECOMP_DESTINATION_DIR
unset PRESERVE_DEAD_CODE_INITS_AND_TERMS
unset PRODUCT_NAME
unset PRODUCT_SETTINGS_PATH
unset PROFILING_CODE
unset PROJECT
unset PROJECT_DERIVED_FILE_DIR
unset PROJECT_DIR
unset PROJECT_FILE_PATH
unset PROJECT_NAME
unset PROJECT_TEMP_DIR
unset PROJECT_TEMP_ROOT
unset RANLIB
unset RECURSIVE_SEARCH_PATHS_FOLLOW_SYMLINKS
unset REMOVE_CVS_FROM_RESOURCES
unset REMOVE_GIT_FROM_RESOURCES
unset REMOVE_HG_FROM_RESOURCES
unset REMOVE_SVN_FROM_RESOURCES
unset REZ_COLLECTOR_DIR
unset REZ_OBJECTS_DIR
unset SCAN_ALL_SOURCE_FILES_FOR_INCLUDES
unset SCRIPT_INPUT_FILE_COUNT
unset SCRIPT_OUTPUT_FILE_COUNT
unset SDKROOT # !
unset SDK_DIR
unset SDK_NAME
unset SDK_PRODUCT_BUILD_VERSION
unset SED
unset SEPARATE_STRIP
unset SEPARATE_SYMBOL_EDIT
unset SET_DIR_MODE_OWNER_GROUP
unset SET_FILE_MODE_OWNER_GROUP
unset SHARED_DERIVED_FILE_DIR
unset SHARED_PRECOMPS_DIR
unset SKIP_INSTALL
unset SOURCE_ROOT
unset SRCROOT
unset STRINGS_FILE_OUTPUT_ENCODING
unset STRIP
unset STRIP_INSTALLED_PRODUCT
unset STRIP_STYLE
unset SUPPORTED_DEVICE_FAMILIES
unset SUPPORTED_PLATFORMS
unset SYMROOT
unset SYSTEM_ADMIN_APPS_DIR
unset SYSTEM_APPS_DIR
unset SYSTEM_CORE_SERVICES_DIR
unset SYSTEM_DEMOS_DIR
unset SYSTEM_DEVELOPER_APPS_DIR
unset SYSTEM_DEVELOPER_BIN_DIR
unset SYSTEM_DEVELOPER_DEMOS_DIR
unset SYSTEM_DEVELOPER_DIR
unset SYSTEM_DEVELOPER_DOC_DIR
unset SYSTEM_DEVELOPER_GRAPHICS_TOOLS_DIR
unset SYSTEM_DEVELOPER_JAVA_TOOLS_DIR
unset SYSTEM_DEVELOPER_PERFORMANCE_TOOLS_DIR
unset SYSTEM_DEVELOPER_RELEASENOTES_DIR
unset SYSTEM_DEVELOPER_TOOLS
unset SYSTEM_DEVELOPER_TOOLS_DOC_DIR
unset SYSTEM_DEVELOPER_TOOLS_RELEASENOTES_DIR
unset SYSTEM_DEVELOPER_USR_DIR
unset SYSTEM_DEVELOPER_UTILITIES_DIR
unset SYSTEM_DOCUMENTATION_DIR
unset SYSTEM_KEXT_INSTALL_PATH
unset SYSTEM_LIBRARY_DIR
unset TARGETED_DEVICE_FAMILY
unset TARGETNAME
unset TARGET_BUILD_DIR
unset TARGET_NAME
unset TARGET_TEMP_DIR
unset TEMP_DIR
unset TEMP_FILES_DIR
unset TEMP_FILE_DIR
unset TEMP_ROOT
unset TEST # Break Makefile OpenSSL build
unset TOOLCHAINS
unset UNSTRIPPED_PRODUCT
unset USER_APPS_DIR
unset USER_LIBRARY_DIR
unset USE_DYNAMIC_NO_PIC
unset USE_HEADERMAP
unset USE_HEADER_SYMLINKS
unset VALIDATE_PRODUCT
unset VALID_ARCHS
unset VERBOSE_PBXCP
unset VERSION_INFO_BUILDER
unset VERSION_INFO_FILE
unset VERSION_INFO_STRING
unset WARNING_CFLAGS
unset XCODE_APP_SUPPORT_DIR
unset XCODE_PRODUCT_BUILD_VERSION
unset XCODE_VERSION_ACTUAL
unset XCODE_VERSION_MAJOR
unset XCODE_VERSION_MINOR
unset XPCSERVICES_FOLDER_PATH
unset YACC
unset arch
unset variant

# Problems with Xcode and boost
export PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin

# Unset environment variables used by pkg-config {
# * http://linux.die.net/man/1/pkg-config
unset PKG_CONFIG_PATH
unset PKG_CONFIG_DEBUG_SPEW
unset PKG_CONFIG_TOP_BUILD_DIR
unset PKG_CONFIG_DISABLE_UNINSTALLED
unset PKG_CONFIG_ALLOW_SYSTEM_CFLAGS
unset PKG_CONFIG_ALLOW_SYSTEM_LIBS
unset PKG_CONFIG_SYSROOT_DIR

# https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html#cross-compiling-for-android
unset ANDROID_NDK
unset ANDROID_NDK_ROOT
unset ANDROID_STANDALONE_TOOLCHAIN

# This variable should be set to empty.
# Example from Ubuntu:
# > (unset PKG_CONFIG_LIBDIR && pkg-config --cflags xorg-wacom) # return default path!
# > (export PKG_CONFIG_LIBDIR="" && pkg-config --cflags xorg-wacom) # nothing found
export PKG_CONFIG_LIBDIR=""
# }
